The antioxidant response of the liver of male Swiss mice raised on a AIN 93 or commercial diet

Background: Reactive oxygen species (ROS) are formed under natural physiological conditions and are thought to play an important role in many human diseases. A wide range of antioxidants are involved in cellular defense mechanisms against ROS, which can be generated in excess during stressful conditions, these include enzymes and non-enzymatic antioxidants. The aim of this study was to evaluate the antioxidant responses of mice to two diets control, commercial and the purified AIN 93 diet, commonly used in experiments with rodents. Results: Malondialdehyde (MDA) and hydrogen peroxide (H2O2) concentrations and superoxide dismutase (SOD) and glutathione reductase (GR) activities determined in the liver were lower in the group of mice fed with the AIN 93 diet, while catalase (CAT) activity was higher in the same group, when compared to the group fed on the commercial diet. Liver glutathione peroxidase (GSH-Px) activity was similar in the groups fed on either AIN 93 or the commercial diets. Two SOD isoforms, Mn-SODII and a Cu/Zn-SODV, were specifically reduced in the liver of the AIN 93 diet fed animals. Conclusions: The clear differences in antioxidant responses observed in the livers of mice fed on the two diets suggest that the macro- and micro-nutrient components with antioxidant properties, including vitamin E, can promote changes in the activity of enzymes involved in the removal of the ROS generated by cell metabolism.

We would like to thank Prof. Dr. Pedro Luiz Rosalen by granting the room for experimentation animals at the College of Odontology of Piracicaba (FOP / UNICAMP) and Fernando Piotto for guidance and supervision on the statistical analysis of all results. This work was supported by Fundação de Amparo à Pesquisa do Estado de São Paulo - FAPESP—Grant n° [04/1381-0] and [08/52721-5]). F.R.C. and R.A.A. would like to thank FAPESP for post-doctoral fellowship (Grant n° 06/60473-6). R.A.A. also thanks the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq, Brazil), for the fellowship granted.